Pearson's Crystal Data: How To's

The list of how to perform special functions as well as tips and tricks
is still
growing. So we would like to point you also to the
function list or to the brochure (see links on the left side) as well as to the tutorial (user manual) of PCD. (Cf.
"Help/Tutorial...".)

How to search e.g. ABX4 or compounds containing H4?

it's a little bit tricky, and the solution is not 1 : 1 identical with that from
ICSD, because an ANX formula is not defined in the Pearson's Crystal Data (PCD)
entries and the oxidation states are normally not defined for the atoms.

Since PCD has a long-term metallurgical history and thus many non-stoichiometric
compounds and more alloys than ICSD, its philosophy is to use concentrations or
concentration ranges in percent, e.g. a ABC4 (ANX4 or MNO4 or .....) composition
is defined as A and B with 16 .. 17 percent each and C with 66 .. 67 percent. (It's
up to you to choose the epsilons, 16.6 .. 16.7 or perhaps 15 .. 18 or so to fetch
more non-stoichiometric compounds. The ANX formula has the disadvantage: What is
with compounds like e.g. A0.98
B1.02 X4 ?)

1) In PCD, please run the command "Search/Quick search...".
2) In the "Quick search" dialog, enter "3" (without the "") right beneath the input
field "Number of elements".
3) Click into input field beneath "Element 1" and enter: "*(16..17)", the same in
field "Element 2".
=> This leads to ABC4 compounds in general.

To come closer to "ABH4", you can choose elements, periods, and/or groups from the
periodic system of elements (PSE).
Example:
1) Click into the input field "Element 1".
2) While holding down the Ctrl key, click on group buttons "1A", "2A", "3B", etc.
To exclude several elements, click on the element, e.g. to exclude "H", chalcogenides
and halogenides as "A" element.
3) In the input field "Element 1", there is now a list of elements, groups, and/or
periods, separated with ";" each (the ";" is to combine these with "OR").
4) Click into the input field "Element 1", and append "(16..17)" behind the element
etc. list, so you have e.g. "Li;Na;K;Rb;Cs;2A;3B;4B;5B;6B;7B;8B;1B;2B;3A;4A;Bi;7P(16..17)"
as search criterion for field "Element 1".
5) Copy the text string from field "Element 1" and paste it into field "Element
2".
6) Click into field "Element 3" and enter "H(66..67)".
=> This leads to ABH4 compounds. (70 of 180,000 entries in release 2009/10).